Re: overheating
DWRIGHT: I have the identical set-up (3.7L 165HP, closed cooling) and run a 180 degree t-stat. I have experienced overheating, but it has always been related to the lower unit impeller or cooling system leak, reducing pressure in the system. Your problem does not sound like overheating, since you're running very cool. I am suspicious of the temps you are getting.<br /><br />First check the cap to determine if it is not holding the appropriate pressure and releasing coolant from the system. This seems to be the likely culprit. Also check the upper exhaust elbow, at idle it should be cool enough to hold if sufficient raw water is circulating.<br /><br />When my temp rises at idle, it's a good sign I'm due to replace the lower unit impeller (every other year). Also check coolant levels when engine is cold. The exhaust elbow resevoir assembly should be filled to the top and the over-flow should fill to the "cold" line. I don't mean to be condescending, just don't know your expereince level.<br /><br />Didn't get into other issues because you didn't specifically report over-heating. There has been an enourmous amount of discussion about overheating with the 470 and 3.7L Mercruiser engines, you can search the forum. Good luck
